What is a cartridge filter?

A cartridge filter cleans pool water by passing it through a pleated polyester fabric element. Water enters the filter tank, flows through the cartridge material, and clean water returns to the pool while dirt and debris accumulate on the cartridge surface.

Unlike sand filters, which use silica sand beds to trap particles, cartridge filters rely on the fabric pleats to capture debris. Unlike diatomaceous earth (DE) filters, which use a powder coating on grids, cartridge filters need no powder reapplication between cleanings. The cartridge itself is the entire filter medium, replaced when it reaches the end of its useful life, typically every 3 to 5 years depending on pool use and water conditions.

Cartridge filters operate at lower pressure than sand or DE systems, which reduces strain on pump equipment and energy costs. They also filter finer particles, making them popular for pools where water clarity is a priority. When a cartridge becomes dirty, it is cleaned by spraying with a garden hose or chemical cleaner, or replaced entirely. Pool contractors in Naples often recommend cartridge filters for residential pools where low maintenance and efficient filtration are desired, or where space is limited since cartridge units are typically more compact than sand filters.